Response of aestivum and durum wheat varieties to elevated CO2 and temperature under OTC condition

An experiment was undertaken during rabi season of 2020-2021 and 2021-2022 at experimental field of Division of Environmental Science, ICAR-Indian Agriculture Research Institute (IARI), New Delhi inside Open Top Chambers (OTCs) to study the growth and physiological response of aestivum (HD 3226) and durum wheat (HI 8627) varieties to elevated temperature and CO2 concentration. Results showed that days to maturity hastened under elevated temperature condition. Photosynthesis rate, leaf area index and tiller number of wheat varieties reduced in elevated temperature treatment while elevated CO2 concentration of 550 ppm was able to partially compensate the reduction. In aestivum variety of wheat, transpiration rate significantly reduced in elevated CO2 plus high temperature interaction treatment than ambient while transpiration rate of durum variety remained unaffected. The negative effect of elevated temperature on aboveground biomass was more in aestivum variety than durum variety. Elevated CO2 concentration compensated reduction in aboveground biomass by 5.9% in HD 3226 (aestivum) and by 3.6% in HI 8627 (durum) varieties under elevated temperature condition. Hence elevated CO2 concentration will be able to partially compensate reduced crop growth in both aestivum and durum wheat varieties under high temperature condition.